Single phase water based energy curable polymers and method of preparing coatings and printing inks

ABSTRACT

Single phase, water based, energy curable compositions and a method of preparing coatings and printing inks from same.

FIELD OF THE INVENTION

This invention relates to water based, energy curable compositionsuseful for preparing coatings and printing inks.

BACKGROUND OF THE INVENTION Description of Related Art

Energy curable coating and ink compositions are typically composed ofmixtures of acrylated derivatives such as oligomeric acrylates andmonomeric acrylates. In most instances, the monomeric materials areemployed in the composition to control the viscosity of the coating orink formulation depending on the particular method of application.However, these monomers often do not react completely duringpolymerization upon energy curing. Unreacted monomers remain as residualcomponents in the dried printing ink or coated film and are subject tomigration by absorption as well as surface contact. This migration ofresidual components can lead to a host of problems such as “odor” and“off-taste” in sensitive packaging applications such as food packaging.Alternatively, solvents are used to reduce or manipulate the formulationviscosity for appropriate applications. However, the use of solvents isoften associated with unacceptable emissions, toxicity, and/or odorlevels for more sensitive product applications.

The undesirable characteristics of residual solvents and monomers inspecialized coatings and inks has spurred advancement of water based,energy curable compositions, aqueous based curing, and the developmentof energy curable processes in the presence of water. While typically apoor solvent for organic compounds and having too high surface tensionto wet many polymer substrates, water in this instance may neverthelessbe the ideal solvent for coating and ink delivery, able to lowerviscosity and volatilize without adding to emissions, toxicity, or odor.The challenge is to formulate water compatibility over a wide range ofcompositions without producing water sensitivity and low rub resistanceafter curing.

An example of an energy curable composition can be found in EP 287,019.This reference, describes a composition wherein the oligomer is acarboxylic acid containing reaction product of a styrene maleicanhydride copolymer and a hydroxy(meth)acrylate. The composition furthercontains an ethylenically-unsaturated reactive diluent, aphotoinitiator, and optionally a thiol. Exposure of the composition toan actinic source, e.g. a UV light source, results in anaqueous-developable material useful in making printing plates andphotoresists. Such a composition would be less useful as a protectivecoating or a binder in ink specifically due to the designed sensitivityto aqueous development which would lead to low rub resistance whencontacted by water.

Another example of an aqueous developable, energy curable compositioncan be found in EP 287,020. This reference describes an oligomericmaterial as the reaction product of a mono(meth)acrylate derivative of acaprolactone diol and styrene-maleic anhydride copolymer. Thecomposition further optionally contains a reactive diluent and aphotoinitiator. Exposure of the composition to a source of actinicradiation results in a solid cured product useful for making printingplates and photoresists wherein the exposed compositions are developedusing an alkaline aqueous developer. Again, such a composition would beless useful as a protective coating or ink binder due to its watersensitivity.

In neither of the above cases is delivery of the composition by aqueoussolution actually described. U.S. Pat. No. 5,665,840 discloses a watersoluble, crosslinkable prepolymer having in its copolymer chain, asmonomeric structural units, a vinyl lactam; a vinyl alcohol; optionallya lower alkane number carboxylic acid vinyl ester; a vinyl crosslinkingagent; and optionally a vinylic photoinitiator. This reference alsodiscloses a process for making prepolymers, as well as crosslinked,water insoluble, polymeric networks particularly useful for makinghydrogels and water absorbing, molded articles such as contact lenses.Because these cross-linked, water insoluble, polymeric networks swellwith water, they would be unsuitable as cured protective coatings andink vehicles where they would exhibit low resistance to mechanicalabrasion when in the presence of moisture.

U.S. Pat. No. 4,745,138 discloses a class of low molecular weight,partial esters of anhydride containing copolymers capable of providingnon-aqueous, energy curable, liquid compositions for production ofradiation-hardenable coatings without the need to employ an inertorganic solvent. These compositions employ monomers containingterminally ethylenically unsaturated groups and maleic anhydridecopolymers characterized by having free anhydride functionalities andare said to be particularly suitable for improving adhesion and thedispersive capabilities of binder resins. The partial esters areproduced by esterifying a fraction of the anhydride groups byring-opening with a hydroxyalkyl acrylic compound or an admixturethereof with a monohydric alkyl alcohol. By virtue of the introductionof hydrophobic substituents (particularly the esters of monohydric alkylalcohols) and the absence of carboxylic acid groups, these compositionscure to films which are more water- and solvent-resistant than thosemade in accordance with the previous references. However, not discussedin this patent are aqueous solutions of these polymers as provided byhydrolysis of the residual anhydride in dilute caustic, the use of thesesolutions to stabilize solutions or colloidal dispersions of other, lesspolar materials, or coating or ink compositions prepared with thesesolutions.

A parallel approach uses solutions of acrylated, hydrophilic oligomersalone or together with the fore-mentioned polymers. Acrylated oligomers(and solutions of polymer resins made with oligomers) have a viscositythat is typically too high to be used directly for making coatings andprinting inks. The use of water as a diluent to lower the viscosity ofenergy curable, acrylated, oligomeric mixtures has been described inU.S. Pat. No. 6,011,078 wherein the mixtures are used for wood and floorcoating applications. The formulations taught in this patent aredispersions or emulsions and require prior evaporation of water followedby exposure to a temperature above the minimum film formationtemperature (MFFT) before exposure to the actinic source. Without filmformation prior to cure, the resultant energy cured, crosslinked polymerhas very weak coherence, lacks adherence to a substrate, and does notprovide the rub resistance required. Further, the additional dryingstep(s) slow the press speed and increase the potential for causingsurface defects (e.g., lower gloss).

Acrylic functional polyesters containing salt structures are describedby M. Philips, J. M. Loutz, S. Peeters, L. Lindekens, Polymers PaintColour J., 183, #4322, p.38 (1993). These are combined with hydrophilicmonomers (e.g., polyethyleneglycol diacrylates) and water to makeradiation curable, protective coatings. The combinations are describedas homogeneous solutions that can be coated and radiation cured by UVwith water-soluble photoinitiators to give rub- and wash-resistanttop-coats. Also, see J. M. Loutz, S. Peeters, L. Lindekens, J. CoatedFabrics, 22, p.298 (1993). In reality, all these formulations are verylimited in the amount of water that can be incorporated and arecomprised of high resin mass fraction (greater than 65 wt. % of vehicle)with consequently high viscosity. Typically, greater than 30 wt. % wateron a total liquids (vehicle) basis causes degraded performance in theexamples provided. Due to this fact, less than 10 wt. % water isrecommended; and even at this water content, “a thermal flash-off stepis recommended in order to avoid the formation of microporosity in thefilm.”

To make water based coatings and inks that: do not require drying priorto cure, cure to well-adhered, offer rub-resistant films, and arecharacterized as low-odor and low-extractable, single phase mixtures ofhighly-functional, acrylated oligomers and polymers in aqueous solutionor in a thermodynamically stable aqueous microemulsion at viscositiesbelow 500 cP (25 deg C., 10 s-1) as tolerated on typical presses (e.g.,flexo, gravure, and rotary screen) are needed. The formulation of suchsystems to contain both hydrophilic and hydrophobic components, highlyfunctional polymers and oligomers, and at water levels exceeding 25 wt.% (not including dispersed solids) to provide control of viscositywithout sacrifice of cure speed is a challenge not met in the prior art.

SUMMARY OF THE INVENTION

The invention is an energy curable, single phase, aqueous compositioncomprising water, an ethylenically unsaturated oligomer, and anethylenically unsaturated resin containing neutralized acidic or basicfunctional groups. Preferably, the components are in such proportionsand structures as to achieve greater than 25 wt. % water at less than 60wt. % resin in the total liquid mass.

In one embodiment of the invention, an energy curable, single phase,aqueous composition is comprised of water and an ethylenicallyunsaturated resin containing neutralized acidic or basic functionalgroups. Preferably, these components are in such proportions as toachieve greater than 26 wt. % water in the total liquid mass.

A further embodiment of the invention is an energy curable, aqueous,printing ink composition comprising a colorant in a single phase vehiclehaving as its components water, an ethylenically unsaturated oligomer,and an ethylenically unsaturated resin containing neutralized acidic orbasic functional groups. Preferably, these components are in suchproportions and structures as to achieve greater than 25 wt. % water atless than 60 wt. % resin in the vehicle portion.

A further embodiment of the invention is an energy curable, aqueousprinting ink composition comprising a colorant in a single-phase vehiclehaving as its components water and an ethylenically unsaturated resincontaining neutralized acidic or basic functional groups. Preferably,these components are in such proportions as to achieve greater than 40wt. % water in the vehicle.

The conditions under which the described compositions are defined assingle phase are given by the temperature, humidity and pressure in theenvironment prevailing at the moment of cure. In addition, it ispreferred that the liquid vehicles of the compositions also be singlephase at ambient temperature, humidity, and pressure.

A further embodiment of the invention is a method for forming an energycured, water resistant coating on a substrate comprising: coating asubstrate with an energy curable, aqueous coating composition, asdescribed herein, then subjecting the coated substrate to an actinicsource prior to removal of the water thereby forming an energy cured,water resistant coating.

A still further embodiment of the invention is a method for printingusing an energy curable, aqueous composition by applying to a substratethe energy curable, aqueous ink compositions as described herein thensubjecting the substrate to an actinic source prior to removal of thewater thereby forming an energy cured, water resistant, printed product.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by use of the accompanyingdrawings.

FIG. 1 is a three-component, triangular, phase diagram in which thecomponents are: (A) water; (B) a partially water soluble oligomer; and(C) a water-soluble, ethylenically unsaturated resin. Each vertex is apure component and each point on and within the diagram corresponds to amass fraction (or expressed as wt. %) of each of the three possiblecomponents such that the sum of mass fractions is 1.0 (or 100 wt. %).Each mass fraction is read by construction of three lines parallel tothe side opposite the vertex for the pure component in question andreading off the intersection of these lines (e.g., a-a′, b-b′, c-c′ forpoint (18)) on the binary blend scales which are the sides of thefigure. We are interested in the low viscosity, single phase regions inthis diagram.

FIG. 2 is a four-component, tetrahedral, phase diagram in which thecomponents are: (A) water; (B) a partially water soluble oligomer; (C) awater soluble, ethylenically unsaturated resin; and (D) a waterinsoluble oligomer. Again, each vertex is a pure component and eachpoint on or within the diagram corresponds to a mass fraction (orexpressed as wt. %) of each of four components such that the sum of massfractions is 1.0 (or 100 wt. %). The mass fractions are read by theintersection of planes parallel to face opposite the vertex for the purecomponent in question with the binary blend scales that are the sides ofthe figure. FIG. 1 is one face of this tetrahedron (where the massfraction of component D is zero). We are interested in the lowviscosity, single phase regions that contain D in this diagram.

DETAILED DESCRIPTION OF THE INVENTION

The present invention teaches the preferred use of single phase,aqueous, energy curable compositions in the manufacture of coatings andprinting inks. These single phase compositions may be formed as ternaryor quaternary solutions or as microemulsions comprised of (A) water; (B)water soluble oligomers; (C) water soluble, ethylenically unsaturatedresin; and optionally, (D) a water insoluble oligomers. These componentsare preferably in such proportions and structures as to achieve greaterthan 25% wt. % water in the total liquid (vehicle) portion with lessthan 60 wt. % of the solubilizing resin. In the single-phase solutionsof the present invention, the resin contains neutralized acidic or basicfunctional groups which renders it soluble in the final aqueouscomposition. Further, in the present invention the proportion of watermay be freely adjusted so as to achieve any target application viscosityand assure complete cure in processes where drying and curing occursimultaneously without inerting.

In the present invention, as in the prior art, water is used largely asa diluent to control the viscosity of the composition. But in contrastto prior art coating formulations, the invention demonstrates a way toextend the compatibility of water in the composition to a much higherlevel than previously achieved. With an increase in water compatibility,we are able to use water to create low odor formulations since we cannow use higher molecular weight (meth)acrylated components while stillmaintaining an appropriately low viscosity. The resin is completelysoluble in water when even partially neutralized, and it is sostructured so as to allow for a single phase mixture (i.e. solutions) ofingredients by functioning as a “solubilizing” aid. To accomplish this,the resin comprises both hydrophobic and hydrophilic segments. Only thewater insoluble oligomer of the major components listed does notcontribute to stabilize an aqueous, single phase composition. Instead,its level is allowed for by the incorporation of hydrophobic elementsinto the resin and the partially water soluble oligomer.

As used herein the term “solution” is intended to have its conventionalmeaning as a homogeneous, single phase mixture formed by dissolving oneor more substances into another substance, i.e. a single phase liquid orsolid. As used herein the term “miscible” is intended to mean that twoor more components form a single phase solution. As used herein the term“water soluble” is intended to mean that a component is miscible inwater over an extensive concentration range, e.g., 0-90 wt. % water ormore in the total mass of the liquid (vehicle) portion, to form a singlephase, binary, aqueous solution. As used herein the term “partiallywater soluble” is intended to mean that a component is miscible in wateronly over a limited concentration range, e.g. 0 to 70 wt. % water, informing a single phase aqueous solution.

As used herein the term “microemulsion” is used to describe a clear,homogeneous, thermodynamically-stable, colloidal suspension of suchsmall particle size that all the attributes of a true solution apply(except perhaps for the wavelength of maximally scattered light). Fromthis point, the term solution will imply that the described result mayalso be achieved by a thermodynamically stable microemulsion. Thisdescription is not to be confused with a metastable emulsion (as, forexample, in an emulsion polymer), a coarser dispersion which is nottruly thermodynamically stable but only kinetically stable. This doesnot imply that such kinetically stable emulsions are not useful inadmixture with the inventive solution, but that the base of theformulation is a solution of the components discussed within which afourth or fifth emulsified component may be dispersed.

The term “energy curable”, as used herein, is intended to mean a freeradical, addition-cured, hardened, polymerizable, or crosslinkablecomposition, material, or system or any addition-cured, hardened, orcrosslinkable composition, material, or system, wherein the curing,hardening, polymerizing, or crosslinking occurs by action of an actinicradiation source such as ultraviolet light (UV), electron beam radiation(EB), and the like. As used herein “actinic radiation” is defined in itsbroadest sense as any radiation that is capable of exposing photographicfilm.

Free radical photoinitiating systems can be incorporated within theaddition-cured systems of the single phase solutions of the presentinvention in order to enhance the curing. Colorants can be incorporatedusing the single phase solutions of the invention as a vehicle toproduce water-based inks having excellent rheology and suitable for awide range of printing applications from ink jet to higher viscositypaste ink applications. The temperatures at which coating compositionsare typically stored and used are about room temperature. Accordingly,those solutions stable at ambient temperature are desirable and achievedwithin the scope of the present invention. In addition, we require thatthe composition also be single phase at the temperature pertaining atthe point of cure.

The energy curable coating compositions of the present invention may bemore fully understood from the following description provided inconnection with FIGS. 1 and 2 of the accompanying drawings. Throughoutthe description herein, similar reference characters refer to similarelements in all figures. The term component includes single molecularspecies (pure components) and mixtures of similar components termedpseudocomponents that partition between phases in the multiple phaseregions of the phase diagram without alteration of the relativeabundance of each component of the pseudocomponent in each phase. Alsoas used herein, the term “major component” is intended to mean acomponent (or pseudocomponent) having greater than 5 wt. % concentrationin the compositions of the present invention. The figures contained inthe drawings are intended only as illustrations of the ternary andquaternary, aqueous, energy-curable compositions of the presentinvention and are not necessarily drawn to scale or to reflect anyactual phase transition boundary between phase regions in the phasediagram.

The region of most interest in the triangular phase diagram (10) in FIG.1 is enclosed by the cross-hatched trapezoidal fragment (15) with itshigh resin content limited by the 60 wt. % resin line; its low resincontent defined by the cloud point curve (12); its low water side by the25 wt. % water line; and its high water side by the resin/water binary(line (A-C). Over this region, the composition is single phase andinventive. The viscosity can be varied by varying the water and/or resinmass fractions to match that required by the press speed and theapplication technique. Curing is rapid by virtue of the lower oxygensolubility in this region.

The phase transition boundary (12), i.e. the cloud point curve, definesthe component concentrations at which the ternary mixture transitionsfrom two phases in region (14) to a single-phase in the sum of regions(15) and (16). It is understood that the phase transition boundary (12)may assume any shape. Further, its placement within the phase diagram(represented by the arrows “< - - - >” about points x, y, and z),depends on the specific partially water-soluble oligomer and specificresin chosen in the ternary mixture as well as other factors such as theexact temperature at the point of cure, the pressure in the nip, andinteraction with other non-major components of the composition such aswetting agents and photoinitiators.

The solubility in water of the partially water-soluble oligomer and thewater-soluble resin is further illustrated by the binary mixture portionof the diagram represented by base (A_B) and base (A_C), respectively.The water/partially water-soluble oligomer mixture concentrations aredefined by points along base (A_B) which contains the cloud point Xwhere a single phase solution converts to a two-phase mixture. Thus,mixtures falling within the base segment (A_X) are two-phase mixtures,while the mixtures falling within the base segment (X_B) aresingle-phase solutions in this illustration. Accordingly, the oligomermay be termed “partially water soluble” for the purposes of thisinvention when the quantity represented by the line segment (A_X) isgreater than 30% of the total segment (A_B).

The water/water-soluble solubilizing resin mixture concentrations aredefined by points along base (A_C) which contains the cloud point Ywhere a single phase solution converts to a two phase mixture. Thus,mixtures falling within the base segment (A_Y) are two phases, whilemixtures falling within the base segment (Y_C) are single phasesolutions. Accordingly, the resin may be termed “water soluble” when thequantity represented by the line segment (Y_C) is greater than 30% ofthe total line segment (A_C).

In FIG. 2, an additional component D, the water insoluble oligomer, hasbeen added. FIG. 1 is reproduced in FIG. 2 as the forward-mosttriangular face of the tetrahedral phase diagram (20) where the massfraction of D is zero. The cloud point curve (12) is also illustrated inthis face. Another important phase boundary (22) is shown on the A-B-Dface which shares one point on the A-B binary with the previouslydiscussed cloud point curve and extends to point D. Referring to theinternal box-like volume segments (19) and (23) of the tetrahedral phasediagram, the phase-transition boundary surface segments b-b′-b″-b′″ (28)and a-a′-a″-a′″ (25) represent regions of an internal cloud pointsurface which defines the component concentrations at which thephase-transition for the quaternary mixture occurs from two phases inconcentration region (24) to a single-phase in concentration region (26)summed over the entire diagram. It is understood that thephase-transition boundary may assume any shape. Further, its placementwithin the phase diagram depends on the specific partially water-solubleoligomer, resin, and water-insoluble oligomer employed in the quaternarymixture as well as other factors such as the exact temperature and theinteraction with other non-major components of the composition.

Water

A major component of the compositions of the present invention is water.Water functions as an odor-free diluent used to adjust the viscosity ofthe composition. Further, water in such quantities as to be retainedwhole or in part in the applied liquid at the point of cure provides thepolymer segment mobility needed for a high degree of cure. And finally,the decreased solubility of oxygen in aqueous media contributes to arapid rate of cure in the absence of inerting. All these benefits areincreased as the proportion of water in the formula is increased. Theviscosity's of these solutions can all be adjusted by adjusting theproportions of the miscible diluent and the remaining oligomer providedthat the resulting liquid remains a single phase liquid, preferably withwater fractions greater than 25 wt. % in the single-phase liquid. Thelatter is an important point not only for the freedom to adjustviscosity but also in order that water above a certain limit be providedat the point of cure to maintain fluidity and low oxygen tension whencuring and drying are occurring simultaneously.

Water Soluble Ethylenically Unsaturated Oligomer

The water soluble oligomer (or the partially water soluble oligomer,vide infra) functions as a lower molecular weight extender. It istypically multifunctional, comprising at least two (meth)acrylategroups. The major requirement other than solubility is that it rapidlybuilds into the network after initiation of polymerization. The wt.ratio of resin to water-soluble oligomer extender generally ranges from2.0 to 0.2, preferably 1.0 to 0.4, and most preferably 0.7 to 0.6. Theexact choice depends on the structure of both the resin and theoligomeric extender and the type of property most desired (e.g., scratchresistance or water resistance).

The water soluble oligomer preferably forms an aqueous solution withinrestricted proportions of the oligomer/water components. Thus, a“partially water soluble oligomer” is an oligomer that is miscible inwater but only over a limited concentration range, e.g. 0-70 wt. % waterin the total mass, to form a single phase aqueous solution. As definedearlier in reference to base segment (A_B) in the accompanying figures,an oligomer is “partially water soluble”, as defined by the phasediagram, when the quantity of oligomer represented by the line segment(A_X) is greater than 30% of the base segment (A_B). Typically, linesegment (A_X) ranges between 30% to about 90% of the total base segment(A_B).

The water soluble oligomer is a further characterized as a monomer ormacromer containing ethylenic unsaturation and which can be polymerizedor cross-linked by free radical polymerization. It also containssufficient water-solubilizing groups such as hydroxyl groups, ethyleneoxide segments, and the like to assure at least 5% water uptake in theoligomer/water binary. Preferably, the water soluble oligomer is, forexample, selected from acrylates, methacrylates or combinations thereof.Typically, the water soluble oligomer will contain one or more acrylateor methacrylate groups. Acrylates or methacrylates useful as watersoluble oligomers in the present invention may, for example, be selectedfrom the group consisting of epoxy acrylates, epoxy methacrylates,polyether acrylates, polyether methacrylates, polyester acrylates,polyester methacrylates, polyurethane acrylates, polyurethanemethacrylates, melamine acrylates, melamine methacrylates, ethoxylatedtrimethanolpropane acrylate, ethoxylated trimethanolpropanemethacrylate, ethoxylated di(trimethanolpropane) acrylate, ethoxylateddi(trimethanolpropane) methacrylate, ethoxylated pentaerythritolacrylate, ethoxylated pentaerythritol methacrylate, ethoxylateddipentaerythritol acrylate, ethoxylated dipentaerythritol methacrylate,ethoxylated neopentaglycol acrylate, ethoxylated neopentaglycolmethacrylate, ethoxylated propylene glycol acrylates, ethoxylatedpropylene glycol methacrylates, polyethylene glycol diacrylates andpolyethylene glycol dimethacrylates. Particularly preferred, oligomersare alkyl epoxy acrylates and alkyl epoxy methacrylates.

The water soluble oligomer component may be a single oligomer or acombination of two or more oligomers as described above. In the case, acombination is used, a single pseudocomponent (B′) is substituted forthe pure component (B) in the phase diagram without any additionalcondition. The employment of pseudo-components to simplify phasediagrams is well known in the art.

Typically, where the oligomer is a partially water soluble oligomer, itaccepts at least 5% water to form an aqueous solution, and preferablyaccepts 10% or more water.

In addition, the water soluble oligomer may be too compatible with water(line (A_X) less than 30% of line (A_B) in FIG. 1). When the watersoluble oligomer (or the blend of water-soluble oligomers) is present ingreater than 50 wt. % of the total solids obtained by evaporation of thewater from the total liquid (vehicle), the water-soluble oligomer (orthe blend) should accept no more than 70 wt. % water in a binary (orpseudo-binary) oligomer-water, single phase liquid solution. The resultof too high water compatibility is that the water resistance of thefinal cured film will be degraded.

Water Soluble, Ethylenically Unsaturated Resin

The water soluble, ethylenically unsaturated resin forms a stable,single phase composition with extensive proportions of theoligomer/water binary components, comprising at least 10 to 80 wt. % ormore water in the total liquid. As defined earlier in reference to theline segment (A_C) in the accompanying figures, a resin is “watersoluble” if, as defined by the phase diagram, the quantity representedby the line segment (C_Y) is greater than 30% of segment (A_C).Typically, line segment (C_Y) ranges between 60% to 95% of the totalbase segment (A_C), although the water soluble resin may form singlephase solutions throughout the concentration range represented by thetotal segment (A_C).

The word resin has its usual connotation for ink and coatings, i.e., ahard solid polymer showing properties typical of higher molecular weightprovided by hydrogen-bonded structures without actually being highmolecular weight. The preferred weight average molecular weight isgreater than 1000 but less than 100,000 daltons, more preferably greaterthan 1000 but less than 50,000 daltons, and most preferably greater than1000 but less than 10,000 daltons.

Further, in the present invention, the water soluble resin is aparticular type of surface-active material that functions as a“solubilizing” agent, capable of assisting in the dissolution of otherwater-insoluble components into aqueous solution. It does this bychemically incorporating substantial hydrophilic (e.g., ionic andhydrogen-bonding groups such as carboxyl) and hydrophobic (e.g.,hydrocarbon) structures (as pendant groups or as main chain segments).For example, the resin may have acid-functional groups (e.g. pendantcarboxylic acid groups) which are partially or totally neutralized witha base (e.g., an amine) to form a water-soluble resin salt.Alternatively, the polymeric resin may have basic functional groups(e.g. amino groups) which are partially or totally neutralized with anacid (e.g. a carboxylic acid) to form a water soluble resin salt.Preferably, the resin contains at least two acrylic groups, methacrylicgroups, or a combination thereof, per molecule; more preferably three tofive per mole; and most preferably more than six such functions permole. The carboxylic acid functional groups, which are neutralized witha base, are in such number as to generate an acid number of greater than80 (mg of KOH to completely neutralize 100 g of resin) to assure watersolubility over at least a portion of the water/resin binary. Andpreferably, the resin also contains hydrophobic substituents (e.g.,esters of aliphatic alcohols) to an extent that generates good pigmentdispersing properties, water resistance, and properties consistent withthe above requirements. Thus a preferred ethylenically unsaturated resinis a neutralization product of a base with an energy curable polymer orresin containing carboxylic acid groups; acrylic groups and/ormethacrylic groups; and esters of hydrophobic alcohols, wherein theneutralization product is a water soluble, acrylated, resin salt.

A particularly preferred energy curable resin is a styrene/maleicanhydride copolymer partially esterified with a hydroxy alkyl acrylateor methacrylate, (e.g., hydroxyethyl acrylate, hydroxyethylmethacrylate, hydroxybutyl acrylate, or hydroxybutyl methacrylate) and amedium chain-length aliphatic alcohol (e.g., n-propanol, n-butanol, amylalcohol, isoamyl alcohol, and the like). By increasing the proportion ofhydroxybutyl (meth)acrylate to hydroxyethyl (meth)acrylate, theproportion of methacrylate to acrylate, the proportion of normal(unfunctional) alcohol to functional or branched alcohol, and theproportion of longer-chain alcohol to shorter-chain alcohol, thehydrophobicity of the resin can be increased. In addition, by decreasingthe proportion of total esterification, increasing the extent ofneutralization of the acid groups by caustic, or by the choice of morehighly hydrated caustic (e.g., lithium hydroxide), the hydrophilicitycan be increased. By use of these tools, the resin can be made to bewater-soluble, to stabilize colloidal dispersions and solutions ofwater-insoluble oligomers, to stabilize pigment dispersions, and yet toresist water in the final cured product.

An example of an energy curable polymer of this type is disclosed in PCTInternational Patent Application WO 99/19369, which is incorporatedherein by reference. Accordingly, a preferred resin salt is a resinconcentrate containing 39-41 wt. % resin solids in water and neutralizedwith ammonia to a pH of 6.5. The resin is energy curable having thegeneral structure:

-   R¹, R²═H, C₁-C₁₈ Alkyl, Phenyl, Toluyl, C₇-C₁₄ Alkaryl, C₄-C₁₂    Cycloalcyl, Cl, F, Br-   R³═C₁-C₁₈ Alkyl, C₄-C₁₂ Cycloalcyl, C₃-C₁₀ Polyester,    —(CR⁶HCH₂—O)_(n)—R⁷, —(CH₂CH₂CH₂CH₂—O)_(n)—R⁷, —R⁵—OCOCHR⁶═CH₂-   R⁴═H, Ammonia, Amine, Alkalimetal-   R⁵═C₁-C₁₈ Alkyl, —(CR⁶HCH₂—O)_(n)—, —(CH₂)₄COOCH₂CH₂—, C₃-C₁₀    Polyester, —CH(OR³)CH₂OC₆H₄OCH₂C(OR³)CH—-   R⁶, R⁷═H, C₁-C₅ Alkyl

While any basic compound (e.g., alkali metal hydroxides such as sodiumhydroxide, potassium hydroxide, or lithium hydroxide or amines such asammonia, alkyl amines, or amine-containing oligomers) may be used toneutralize the acidic groups of the resin, ammonia, amines orcombinations thereof, are preferred. A preferred base is selected fromtertiary amines. In a particularly preferred embodiment, the base is anethylenically unsaturated tertiary amine as described in U.S. Pat. No.6,559,222. With selected, alcohol functional, ethylenically unsaturated,tertiary polyamines as neutralizing agents, the acid groups on the resinmay be totally neutralized to form a cross-linkable, water solubleionomer. The ethylenically unsaturated tertiary amine provides thecounter ion of the acidic resin and allows the ionomer formed to“stereo” polymerize during photoreaction to form an additionalcross-linked network over the ethylenically unsaturated groups as wellas over the ionic structure. Unlike other water based, energy curable,resin technologies (wherein the water resistance is imparted to theresin film by the evaporation of ammonia, for example, which shifts theacid base equilibrium in the post-cured material), here by using anethylenically unsaturated base, the neutralized resin forms anadditional cross-linked network instantly on both sides of the ionomerby radiation induced free radical addition polymerization. The result isan energy cured film having enhanced solvent and water resistance fromthe interpenetrating network of covalent and ionic bonds and improvedgloss from more rapid surface cure.

Water Insoluble Ethylenically Unsaturated Oligomers

The water insoluble oligomers suitable for use in the present inventionare energy curable and form two phase mixtures with water withinextensive proportions of the water insoluble oligomer/water binarycomposition space (line segment (A_D) in FIG. 2). As defined earlier inreference to the line segment (A_D) in the accompanying FIG. 2, thewater insoluble oligomer is typically insoluble over the totalwater/oligomer concentration range represented by the segment (A_D).However, an oligomer which is capable of incorporating 5 wt. % water orless is also included as water insoluble for the purpose of thisinvention.

While the water insoluble oligomer typically is totally immiscible inwater, the water insoluble oligomer may form a solution with the watersoluble oligomers within extensive proportions of the (water insolubleoligomer)/(water soluble oligomer) binary compositions. The waterinsoluble oligomer is preferably miscible in the water soluble oligomerover an extensive concentration range, e.g., 5 to 95 wt. % waterinsoluble in the total blend, to form a single phase, binary solution.Typically, the water insoluble oligomers are compounds (or mixtures ofsimilar compounds), which have one, two, or more terminal ethylenicallyunsaturated groups. Representative of such compounds, for example,include: dipropylene glycol diacrylate; tripropylene glycol diacrylate;butanediol diacrylate; hexanediol diacrylate; alkoxylated hexanedioldiacrylate; trimethyol propane triacrylate; alkoxylated trimethylolpropane triacrylate; di(trimethylol propane triacrylate);glycerolpropoxy triacrylate; pentaerythritrol triacrylate; alkoxylatedpentaerythritrol triacrylate; di(pentaerythritrol triacrylate);neopentaglycol diacrylate; alkoxylated neopentaglycol diacrylate;dipropylene glycol dimethacrylate; tripropylene glycol dimethacrylate;butanediol dimethacrylate; hexanediol dimethacrylate; alkoxylatedhexanediol dimethacrylate; trimethyol propane trimethacrylate;alkoxylated trimethylol propane triamethcrylate; di(trimethylol propanemethtriacrylate); glycerolpropoxy trimethacrylate; pentaerythritroltrimethacrylate; alkoxylated pentaerythritrol trimethacrylate;di(pentaerythritrol trimethacrylate); neopentaglycol dimethacrylate;alkoxylated neopentaglycoldimethacrylate; and the like and combinationsthereof. The water-insoluble oligomer may contain a combination ofdiacrylic and triacrylic monomers along with a monomer containing asingle terminal ethylenic group. The water insoluble oligomers may beacrylated epoxy resins; bis acrylic esters of bisphenol A; acrylatedpolyurethanes; acrylated polyesters; acrylated polyether and the like.Preferred water-insoluble oligomers of this type includedi-(3-methacryloxy-2-hydroxypropyl ether of bisphenol-A;di(2-methacryloxyethyl ether of bisphenol-A;di-(3-acryloxy-2-hydroxypropyl ether of bisphenol-A; di(2-acryloxyethylether of bisphenol-A; and the like.

Binary Single Phase Aqueous Solutions Containing Resins

A binary, single phase, aqueous embodiment of this invention is anenergy curable, single phase, aqueous composition comprising a singlephase solution of water and a water soluble, ethylenically unsaturatedresin salt wherein the resin salt is comprised of, for example, theneutralization product of ammonia, an amine or an ethylenicallyunsaturated tertiary amine and an ethylenically unsaturated resincontaining acidic-functional groups. As discussed previously inconnection the water soluble, ethylenically unsaturated resin salt, theethylenically unsaturated resin contains acrylic groups, methacrylicgroups or a combination thereof and is neutralized by ammonia, an amineor an ethylenically unsaturated tertiary amine to form the resin salt.The nature of the water soluble, ethylenically unsaturated resin saltand the water soluble oligomer has been discussed above, and thosediscussions apply to this embodiment of the invention.

Ternary Single Phase Aqueous Compositions Containing Water SolubleOligomers and Resins

FIG. 1 illustrates the ternary, single phase, energy curablecompositions of this invention. This embodiment is an energy curable,aqueous composition comprising a single phase solution of water; a freeradical addition-polymerizable, water soluble oligomer or alternativelya partially water soluble oligomer; and a water soluble, ethylenicallyunsaturated resin salt. The general nature of this embodiment wasdiscussed above. Likewise, the natures of the water soluble,ethylenically unsaturated resin salt and the water soluble oligomer havebeen discussed above. These discussions apply to this embodiment of theinvention.

The limit of water solubility of the oligomer is expressed by theposition of Point X in FIG. 1. In this invention, it is preferred that Xcomprise more than 10 wt. % and less than 70 wt. % water and mostpreferred that X comprise more than 20 wt. % and less than 40 wt. %water. If point X comprises less than 10 wt. % water (is too close topoint B), the two-phase region ((14) in FIG. 1) will be too large,extending so far towards point C at point Z that the resulting singlephase solutions above point Z become too viscous for use in commongraphic arts applications. Similarly, if point X comprises more than 70%water, the resulting cured polymer will be too water-sensitive to beuseful as a protective coating.

The preferred ternary compositions comprise stable, single phasecompositions within region (15) in phase diagram (10) of FIG. 1. Theproperties of the preferred compositions within this region can beadjusted by the choices of oligomer A and resin C as will be apparentfrom the Examples, below.

Quaternary Single Phase Aqueous Compositions Containing Water InsolubleOligomers Water Soluble Oligomers and Resins

FIG. 2 illustrates the quaternary, single phase, energy curablesolutions of this invention. This embodiment is an energy curable,aqueous composition comprising a single phase composition of water; afree radical addition-polymerizable, water soluble oligomer or,alternatively, a partially water soluble oligomer; a free radicaladdition-polymerizable, water insoluble oligomer, and a water soluble,ethylenically unsaturated resin salt. The general nature of thisembodiment was discussed above. Likewise, the nature of the watersoluble, ethylenically unsaturated resin salt, the water solubleoligomer and the water insoluble oligomer has been discussed above, andthose discussions apply to this embodiment of the invention.

The region of most interest in FIG. 2 is a volume of limited extensiontoward the water insoluble component (D) which originates in the singlephase region of face ABC (identical to FIG. 1) near the cloud pointcurve (12). Its general shape in the (D) direction is indicated by thecloud point curve (22) in the ABD face that quickly limits the watercontent to below 25 wt. % of the total liquid in the single phase regionto the left of the A′B′C′ plane (toward higher (D)). Thus the presentinvention is limited to the region bound between plane A′B′C′ on theleft and the ABC plane on the right, by the 25 wt. % water plane on thebottom and the complex surface which is the cloud point surface whichapproximately follows the planes (a,a′,a″,a′″) and (b,b′,b″,b′″) summedover the entire tetrahedral space. Alternatively, the extent of thequaternary, single phase region is controlled by the total amount ofhydrophobic material component (D) including that portion coming fromthe partially water soluble component (B) and any coating or curingadditive (vide infra) which a given structure and amount of the resin(C) can compatibilize with substantial water.

The addition of (D) to water-rich point (23) transitions from a singlephase solution to a composition which is more likely to be anoil-in-water microemulsion (o/w) near the plane (a,a′,a″,a′″) in whichthe continuous phase is aqueous with microscopically small disperseddomains of (D), smaller in diameter than the wavelength of visiblelight. Similarly, the addition of (D) to oil-rich point b′ near the ABaxis transitions from a single phase solution to a composition which ismore likely to be a water-in-oil microemulsion (w/o) near the plane(b,b′b″,b′″) in which the continuous phase is largely oligomer B withmicroscopically small dispersed domains of (D) dispersed within.

By adjusting the balance between the number and nature of thehydrophobic ester groups (to compatibilize the resin with thewater-insoluble oligomer) and the extent and nature of theneutralization of the acid groups (to compatibilize the resin with thewater and water-soluble oligomer), the single phase volume within FIG. 2can be increased. When successful, there exist single phase, quaternarycompositions at such proportions that they contain greater than 25 wt. %water and greater than 5 wt. % (D) that are particularly useful in thedirect cure of inks and coatings based on these compositions as vehiclewithout prior drying.

Free Radical Photoinitiator

Any of the previously described energy curable, single phase, aqueouscompositions of this invention may contain a photoinitiator. Unless thecomposition is formulated specifically for use with electron beamcuring, the energy curable composition will typically contain anaddition polymerization photoinitiator that generates free radicals uponexposure to actinic radiation, such as ultraviolet light. Such aphotoinitiator has one or more compounds that directly furnish freeradicals when activated by actinic radiation. The photoinitiator mayalso contain a sensitizer that extends the spectral response into thenear ultraviolet, visible or near infrared spectral regions. In freeradical initiated curing systems, typically irradiation of aphotoinitiator produces free radicals that initiate polymerizationand/or crosslinking. Typically, only small amounts of photoinitiator arerequired to effectively initiate a polymerization, e.g. from about 0.5wt.% to about 5 wt. % based on the total weight of the polymerizable(curable) solution. Typically, the photoinitiator is readily soluble inat least one of the major components of the energy curable solution; andit is preferably at least partially soluble in water. Still morepreferably, the free radical curing system comprises a photoinitiatorthat is substantially soluble in one or more of the major components inthe single phase solution of the present invention. A wide variety ofphotoinitiators may be used in the aqueous compositions of thisinvention. Useful photoinitiators of this type are, for example,described in a review by B. M. Monroe and G. C. Weed entitled“Photoinitiators for Free-Radical-Initiated Photoimaging Systems”, Chem.Rev. 1993, 93, 435-448, which is incorporated herein by reference.Preferred photoinitiators, suitable for use alone or in combination withother photoinitiators, are Irgacure 1173, Irgacure 500, Irgacure 184,Irgacure 2959 (Irgacure is a trademark and commercially availableproduct of Ciba Specialty Additives, Tarrytown, N.Y.), Esacure KIP 150,Esacure KIP EM and Esacure KIP DP 250 (Esacure is a Trademark andcommercially available product of Lamberti, Gallarate, Italy).

Energy Curable Inks Prepared from Single Phase Aqueous Solutions

As used herein, the term “ink” or “printing ink” has its conventionalmeaning, i.e., a colored liquid composed of a colorant (which istypically a pigment), dispersed in a liquid vehicle. In particular, theenergy curable ink of the present invention comprises: a pigment and anenergy curable liquid vehicle being the energy curable, single phase,aqueous compositions of this invention having been fully describedabove. In particular, the energy curable, liquid vehicle is a singlephase, aqueous solution of water, oligomer, and a water soluble,ethylenically unsaturated resin containing neutralized acidic or basicfunctional groups. As discussed above, the oligomer can either be apartially water soluble oligomer, a water soluble oligomer, orcombination thereof. A further alternative energy curable liquidvehicle, comprises an energy curable, single phase, aqueous solution ofwater and a water soluble, ethylenically unsaturated resin salt havingneutralized acidic and basic functional groups, as discussed above.

Colorants

The energy curable inks of this invention contain one or more colorantsin the form of a dye or pigment dispersed therein. Pigments suitable foruse in the present invention include conventional organic or inorganicpigments. Representative pigments may, for example, be selected from thegroup Pigment Yellow 1, Pigment Yellow 3, Pigment Yellow 12, PigmentYellow 13, Pigment Yellow 14, Pigment Yellow 17, Pigment Yellow 63,Pigment Yellow 65, Pigment Yellow 73, Pigment Yellow 74, Pigment Yellow75, Pigment Yellow 83, Pigment Yellow 97, Pigment Yellow 98, PigmentYellow 106, Pigment Yellow 111, Pigment Yellow 114, Pigment Yellow 121,Pigment Yellow 126, Pigment Yellow 127, Pigment Yellow 136, PigmentYellow 138, Pigment Yellow 139, Pigment Yellow 174, Pigment Yellow 176,Pigment Yellow 188, Pigment Yellow 194, Pigment Orange 5, Pigment Orange13, Pigment Orange 16, Pigment Orange 34, Pigment Orange 36, PigmentOrange 61, Pigment Orange 62, Pigment Orange 64, Pigment Red 2, PigmentRed 9, Pigment Red 14, Pigment Red 17, Pigment Red 22, Pigment Red 23,Pigment Red 37, Pigment Red 38, Pigment Red 41, Pigment Red 42, PigmentRed 48:2, Pigment Red 53:1, Pigment Red 57:1, Pigment Red 81:1, PigmentRed 112, Pigment Red 122, Pigment Red 170, Pigment Red 184, Pigment Red210, Pigment Red 238, Pigment Red 266, Pigment Blue 15, Pigment Blue15:1, Pigment Blue 15:2, Pigment Blue 15:3, Pigment Blue 15:4, PigmentBlue 61, Pigment Green 7, Pigment Green 36, Pigment Violet 1, PigmentViolet 19, Pigment Violet 23, Pigment Black 7. Pigment compositionswhich are a blend of conventional pigment and poly(alkylene oxide)grafted pigments are also suitable for use in the energy curable inks ofthis invention and are described in U.S. Pat. Nos. 4,946,508; 4,946,509;5,024,698; 5,024,894; and 5,062,894 each of which is incorporated hereinby reference.

Adjuvants

The energy curable compositions and inks of this invention may containthe usual adjuvants to adjust flow, surface tension and gloss of thecured coating or printed ink. Such adjuvants contained in inks orcoatings typically are a surface-active agent, a wax, or a combinationthereof. These adjuvants may function as leveling agents, wettingagents, dispersants, defrothers or deaerators. Additional adjuvants maybe added to provide a specific function such as surface slip. Preferredadjuvants include fluorocarbon surfactants such as FC-4430 (commerciallyavailable product of the 3M Company, St Paul, Minn.); silicones such asDC57 (commercially available product of Dow Chemical Corporation,Midland, Mich.), Byk 024, Byk 019, Byk 023, Byk 373, Byk 381, Byk 3500,Byk 3510, Byk 3530, Byk 361, Byk 363 (commercially available products ofByk Chemie, Wesel, Germany) Foamex N, Foamex 8030, Foamex 810, Airex900, Tegorad 2100, Tegorad 2200N, Tegorad 2250N, Tegorad 2500, Tegorad2600 (Foamex, Airex and Tegorad are trademarks and are commerciallyavailable products of Tego Chemie, Essen, Germany.), Addid 700, Addid810, Addid 840, Addid 300, Addid 310, Addid 320 (Addid is a trademarkand commercially available from Wacker Silicones Corp., Adrian, Mich.);organic polymer surfactants like, Solspers 24000, Solspers 32000,Solspers 41090, Solspers 20000, Solspers 27000 (Solspers is a trademarkand commercially available from United Color Technology, Inc., Newton,Pa.) Disperbyk 168, Disperbyk 184, Disperbyk 190, Disperbyk 192(Disperbyk is a trademark and commercially available from Byk Chemie,Wesel, Germany.), Wet 500, Wet 505, Airex 920, Airex 910, Dispers 610,Dispers 605, Dispers 740, Dispers 750 and Dispers 760 (Dispers, Wet andAirex are trademarks and are commercially available from Tego Chemie,Essen, Germany.) Surfanol 105E, Surfanol 420, Dynol 604 (Surfanol andDynol are trademarks and are commercially available from Air Productsand Chemicals Inc., Allentown, Pa.); polyethylene wax; polyamide wax;polytetrafluoroethylene wax; and the like.

Preparation of Energy Cured Film

An embodiment of this invention is a method of forming a film and/or aprinted ink image. Thus, the energy curable compositions of thisinvention may be applied to a variety of substrates and cured by avariety of methods for applications that include protective, decorativeand insulating coatings; potting compounds; sealants; adhesives;photoresists; textile coatings; and laminates on a variety ofsubstrates, e.g., metal, rubber, plastic, wood, molded parts, films,paper, glass cloth, concrete, and ceramic. The energy curablecompositions of this invention are particularly useful in themanufacture of coatings and printing inks for use in a variety ofGraphic Art applications and printing processes. Advantageously, thesingle phase compositions of this invention cure without the priorremoval of water. Moreover, the single phase, energy curablecompositions derived therefrom, are particularly useful in the wet-trapprinting applications as disclosed in co-pending patent application U.S.Ser. No. 10/079,781 which was filed with the United States Patent andTrademark Office on Feb. 19, 2002, and incorporated herein by reference.

The embodiment of this invention directed to a method for forming acured, water-resistant ink or coating on a substrate comprises applyingto a substrate the energy curable, single phase, aqueous compositions ofthe invention to form a layer and subsequently subjecting the coatedsubstrate to a source of actinic radiation. However, if the method isspecifically directed to forming a water-resistant ink, the methodadditionally requires adding a colorant to the aqueous composition. Theenergy curable, aqueous composition may be any of the energy curable,aqueous compositions of this invention. Thus, the composition maycomprise a single phase solution of water; an ethylenically unsaturatedoligomer; and an ethylenically unsaturated resin containing neutralizedacidic or basic functional groups. The oligomer employed may be apartially or a completely water soluble oligomer or may be a combinationof partially water soluble, completely water soluble and water insolubleoligomers. Alternatively, the composition may comprise a single phasesolution of water and an ethylenically unsaturated resin containingneutralized acidic or basic functional groups. As previously describedthe energy curable, aqueous composition may additionally require addinga photoinitiator, an adjuvant or a combination thereof.

The aqueous composition may be applied to the substrate surface as acoating in a uniform layer using any conventional coating technique.Therefore, compositions of the present invention may be applied by spincoating, bar coating, roller coating, curtain coating or by brushing,spraying, etc. Alternatively, the aqueous composition may be appliedimage-wise to a substrate surface, for instance as a printing ink, usingany conventional industrial printing technique including flexographic,gravure, screen, lithographic, and ink jet printing.

The actinic radiation initiated cure is most effectively done with thewater of the formula in place. Water as solvent lowers the viscositypermitting the reactive sites of polymerization to diffuse in the systemand to propagate effectively to generate longer chains. The viscositypoint at which effective reaction ceases is known as the vitrificationpoint. In the presence of water above a critical level, a very lowresidual Functionality remains after initiation of the polymerization,as vitrification is delayed by the decreased viscosity. Water alsodecreases the level of dissolved oxygen in the coating. This fact leadsto more rapid cure as well.

From the moment the coating or ink of the present invention is applied,water starts evaporating. UV lamps and electron beams under nitrogenflow provide heat and gas flow that accelerates water removal. Dependingon the characteristics of the particular cure unit operating as a dryer,there is a maximum level of water that will be removed per unit time inthe curing zone. Without implying a limit, it is evident from thediscussion above that a certain fraction of water must remain in thecoating at the point of exit from the cure unit. In most cases, however,less water than the measured maximum can be coated without increasingthe residual acrylic unsaturation, i.e., the rate of drying slows as thecritical limit is approached. In our experience, the practical lowerlimit is ⅓ of the amount estimated from the maximum drying capacity.Characteristic of having water in place at the point of cure, theliquids of the present invention at greater than 25 wt. % water in theliquid phase cure to such complete conversion that no acrylateunsaturation can be detected by the usual reflection infrared techniquesused in the industry.

Substrate

The substrate and its surface may be composed of any typical substratematerial such as plastics, metals, composites, papers, etc.; and theenergy cured film or layer on the substrate may be used in a variety ofapplications. The substrate may be print stock typically used forpublications or may be a packaging material in the form of a sheet, acontainer such as a bottle or can, or the like. In most instances, thepackaging material is a polyolefin such as a polyethylene or apolypropylene, a polyester such as polyethylene terphthalate, or a metalsuch as an aluminum foil, a metalized polyester, or a metal container.Once the aqueous, single phase, energy curable composition is applied tothe packaging material it may be used to contain any kind of liquid orsolid material such as foods, drinks, cosmetics, biological materials orspecimens, pharmaceuticals, etc.

The single phase, energy curable, aqueous compositions of this inventionwill low be illustrated by the following examples, however, thespecification is not intended o be limited thereby.

EXAMPLE 1

To make example 1a, a water-soluble, ethylenically unsaturated, resinsalt (53.8 g, resin concentrate containing 39 wt. % resin solids inwater and neutralized with ammonia to pH 6.5 (2.7 g 12 N), as describedin PCT International Patent Application WO 99/19369) was added to apartially water soluble, ethylenically unsaturated, acrylate-functionaloligomer (11.0 g, Laromer 8765, Laromer is a trademark and commerciallyavailable product of BASF Corporation, Mount Olive, N.J.) and water(32.5 g). Using the same procedure as given for 1a, examples 1b, 1c 1d,1e, and 1f as (amounts reported in Table 1) were assembled ashomogeneous, single-phase compositions. Coating viscosity was measuredusing a rheometer at 10 s-1 and 25 deg C. (AR 1000-N, available from TAInstruments, New Castle, Del.) having a 4 cm, 2 deg. cone and plategeometry installed.

TABLE 1 Resin LR 8765 Viscosity Coating Water Concentrate Oligomer PasExample pph of Total pph pph 25 C., 10s−1 1a 68.0 53.8 11.0 0.253 1b58.5 52.6 21.0 0.259 1c 48.0 51.3 32.0 0.303 1d 37.5 50.0 43.0 0.299 1e30.5 50.0 50.0 0.292 1f 24.4 40.0 60.0 0.190

This example illustrates the assembly of ternary, single phase, aqueous,energy curable, coating compositions at useful viscosities containing apartially water soluble, ethylenically unsaturated oligomer; 15-21 wt. %of a water soluble, ethylenically unsaturated, resin ammonium salt; andover a range of 30-68 wt. % water. Solution If is a comparative examplebelow 25 wt. % water.

EXAMPLE 2

Industrial coatings were prepared using the single phase, aqueous,energy curable, coating compositions described in Examples 1a-1f after awetting agent (0.25 g DC-57, a product of Dow Corning, Wildwood, Mo.)and a photoinitiator (1.0 g) er added to a 50 g aliquot of eachcomposition. In this example, the coatings were applied to apolypropylene substrate (Mobil ASW, Exxon-Mobil Corp., Macedon, N.Y.)using a #3 wire-wound rod at variable rod speeds so as to place a rangeof wet coating weights on the film surface. The coatings were cured bypassing under an ultra-violet lamp yielding a dose of 175 mJ/cm² (twomedium pressure Hg lamps at 200 W/in each, 200 fpm on a UV Processorfrom RPC Industries, Plainfield, Ill. in air) within five seconds of thewet application. The resulting physical property and film performancedata were measured for each coating after conditioning the film at 75 Fand 48% RH for one day.

Water and alcohol or solvent (more specifically methylethylketone orMEK) rubs were determined by wetting the cured coated substrate withwater or MEK and employing light finger pressure to rub (back and forthis one rub cycle) the coating off the substrate until a break-through tothe original substrate surface is detected. The number of rub cyclesrequired for break through was then recorded. Coating gloss was measuredat a 60-degree angle using a calibrated micro-gloss meter (type DINGeproft 4501, available from BYK Gardner). Scratch resistance wasdetermined by the Hoffman method using the Modified HoffmanScratch-Hardness Tester (SG-1610-M, available from Gardner Laboratory,Bethesda Md.). The number reported is the mass bearing on the metalcuticle that first breaks through the coating to expose the base.

The coating weight was determined gravimetrically by the difference inweight between a 10 cm×10 cm piece cut from the coated area and anidentical size piece cut from a similar area of uncoated stock. Eachattribute reported in Table 2 is normalized to 2.4 g/sqm dry coatingweight by interpolation of the raw data as a function of coating weight.

TABLE 2 Viscosity Example (Pa · s.) Gloss (%) Scratch (g) Water Rub MEKRub 1a 0.253 83 100 16 12 1b 0.259 83 275 22 14 1c 0.303 86 325 26 16 1d0.299 89 400 18 18 1e 0.292 85 50 16 16 1f 0.190 80 25 13 10

This example shows a strong peak in mechanical properties atcompositions with 35-50 wt. % water not anticipated by the literature.The increase in mechanical strength from 1a to 1c is most likely theresult of an increase in acrylate molar concentration, but thesubsequent falloff toward lower water content is a specific rate andextent of cure effect of the solvent. Thus we prefer water at a higherlevel than would be suggested to be advantageous based on theliterature.

EXAMPLE 3

To a water insoluble, ethylenically unsaturated oligomer (11 g, Laromer8945) was added a partially water soluble, ethylenically unsaturated,acrylate-functional oligomer (47 g, Laromer 8765) and a water soluble,ethylenically unsaturated, resin ammonium salt (42 g, resin concentratecontaining 39 wt. % resin solids in water and neutralized with ammoniato pH 6.5, as described in PCT International Patent Application WO99/19369).

This example illustrates the assembly of a quaternary, single phase,aqueous, energy curable, coating composition containing a waterinsoluble, ethylenically unsaturated oligomer; a partially watersoluble, ethylenically unsaturated oligomer; with only 16.4 wt. % of awater soluble, ethylenically unsaturated, resin ammonium salt; and 26wt. % water.

EXAMPLE 4

To the aqueous resin salt described in U.S. Pat. No.6,559,222 (58.0 g,resin concentrate containing 41.5 wt. % resin solids in water,amine-neutralized (Sun 924-1069, of Sun Chemical Corporation, Fort Lee,N.J.) to pH 6.5) was added a partially water soluble, ethylenicallyunsaturated oligomer (42.0 g, Laromer 8765).

This example illustrates the assembly of a ternary, single phase,aqueous, energy curable, coating composition containing 24 wt. % of apartially water soluble, ethylenically unsaturated, resin amine salt, apartially water soluble, ethylenically unsaturated oligomer, and 34 wt.% water.

EXAMPLE 5

To the aqueous resin salt described in U.S. Pat. No. 6,559,222 (58.0 g,resin concentrate containing 41.5 wt. % resin solids in water, amineneutralized (Sun 924-1069, of Sun Chemical Corporation, Fort Lee, N.J.)to pH 6.5) was added a partially water soluble, ethylenicallyunsaturated oligomer (42.0 g, Laromer 8765). To this mixture is added aphotoinitiator (3.0 g, Igracure 2959, Igracure is a trademark andcommercially available product of Ciba Specialty Chemicals, Tarrytown,N.Y.). The mixture was then stirred until the photoinitiator dissolved.

This example illustrates the assembly of a ternary, single phase,aqueous, energy curable, coating composition containing 24 wt. % of apartially water soluble, ethylenically unsaturated, resin amine salt, apartially water soluble, ethylenically unsaturated oligomer, 31 wt. %water and a photoinitiator.

EXAMPLE 6

To a water soluble, ethylenically unsaturated, resin salt (51.3 g, aresin concentrate containing 39 wt.% resin solids in water andneutralized with ammonia to pH 6.5 and described in PCT InternationalPatent Application WO 99/19369) was added a partially water-soluble,acrylate-functional oligomer (32.0 g, Laromer 8765), and water (16.7 g).To this mixture was added a photoinitiator (3.0 g, Igracure 2959), andthe mixture was stirred until the photoinitiator dissolved.

This example illustrates the assembly of a ternary, single phase,aqueous, energy curable, coating composition containing 19.5 wt. % of awater-soluble, ethylenically unsaturated, resin ammonium salt, apartially water soluble, ethylenically unsaturated oligomer, 47 wt. %water and a photoinitiator.

EXAMPLE 7

To the aqueous resin salt described in PCT International PatentApplication WO 99/19369 (85.1 g, a resin concentrate containing 39 wt. %resin solids in water and neutralized with ammonia to pH 6.5) was addedwater (41.9 g).

This example illustrates the assembly of a binary, single phase,aqueous, energy curable, coating composition containing a water soluble,ethylenically unsaturated resin and 74 wt. % water.

EXAMPLE 8

To the aqueous, resin salt described in PCT International PatentApplication WO 99/19369 (85.1 g, a resin concentrate containing 39 wt. %resin solids in water and neutralized with ammonia to pH 6.5) was addedwater (41.9 g). To this mixture a photoinitiator (3.0 g, Igracure 2959)was added, and the mixture stirred until the photoinitiator dissolved.

This example illustrates the assembly of a binary, single phase,aqueous, energy curable, coating composition containing a water soluble,ethylenically unsaturated resin, 72 wt. % water, and a photoinitiator.

EXAMPLE 9

Industrial coatings were prepared using the single phase, aqueous,energy curable, coating compositions described in Examples 1 to 8 aftera wetting agent (0.5 g DC-57, a product of Dow Corning, Wildwood, Mo.)was added to each coating composition. In this example, the coatingswere applied to the substrate using a #3 wire-wound rod then cured onthe substrate surface using either an electron beam with 3 Mrad dose at175 kV (AEB Lab 105 from Advanced Electron Beam, Inc., Wilmington, Mass.under nitrogen at less than 100 ppm oxygen), or an ultra-violet lampwith 175 mJ/cm² dose (two medium pressure Hg lamps at 200 W/in each, 200fpm on a UV Processor from RPC Industries, Plainfield, Ill. in air). Theresulting physical property and film performance data was measured foreach coating after conditioning the film at 75 F and 48% RH for one day.

Coating adhesion was measured by taking a convenient length of 600 or610 tape (available from 3M Co., St Paul, Minn.) and laminating the tapeto the cured surface under finger pressure then lifting the tape fromthe surface in one rapid motion. A coating was rated “pass” when thecoating remained completely intact and adhered to the substrate. Acoating was rated a “fail” when damage to the coating or any removaloccurred.

For comparison of the impact of the pre-drying method on the coatingproperties coating examples 1c, 3, 4, 5, and 6 were first applied andcured in less than 15 sec from application (without pre-drying) and thenapplied, dried in air for an hour at 40 C., and cured under identicalpower settings (after pre-drying). The results of the performance testsfor each coating are described in Table 3.

TABLE 3 Pre- 60 Cure drying Viscosity Water MEK DEG Adhesion AdhesionExample System Method Substrate Method (Pa · s.) Rubs Rubs Gloss 610Tape 600 Tape  1c Ternary EB Coated PP¹ No 0.31 30 19 91 pass pass 3Quaternary EB Cardboard² No 0.32 36 18 83 pass fail 4 Ternary EB Paper³No 0.46 60 29 85 pass pass 5 Ternary UV Paper⁴ No 0.44 61 26 88 passpass 6 Ternary UV Coated PP⁵ No 0.34 20 21 83 pass fail 7 Binary EBCoated PP⁵ No 0.21 40 6 80 pass fail 8 Binary UV Coated PP⁵ No 0.21 38 678 pass fail  1c Ternary EB Coated PP¹ Yes 0.31 9 2 88 fail fail 3Quaternary EB Cardboard² Yes 0.32 18 9 80 fail fail 4 Ternary EB Paper³Yes 0.46 27 17 77 fail fail 5 Ternary UV Paper⁴ Yes 0.44 21 14 88 passfail 6 Ternary UV Coated PP⁵ Yes 0.34 8 8 83 pass fail ¹saran coatedpolypropylene, Mobil ASW, available Exxon-Mobil Corp., Macedon, NY²uncoated cardboard, Leneta Form N2A-Opacity, available Leneta Co.,Mahwah, NJ ³clay coated paper, #50 SAPPI, available Sappi Fine PaperN.A., SD Warren Co, Boston, MA ⁴clay coated paper, #23 Strathmore,available Strathmore Papers, East Granby, CT ⁵saran coatedpolypropylene, Mobil ASW, printed with Sun OP Lam, available SunChemical Corporation, Fort Lee, NJ

This example further demonstrates the improvement in cure-relatedproperties when water remains in the coating at the point of cure.Gravimetric measurements indicate that this retained water is typically15 wt. % of the coated dry weight (or approximately ⅓ of the coatedwater in Example 1c) at the exit from the photoreactor in the examplewithout pre-drying. Drying in this instance is accomplished as anindirect result of the heat from the UV lamps and/or the by the nitrogeninerting in the case of electron beam curing. In the pre-dried examplefrom 1c, less that 1% of the coated water was detected. Clearly, dryingbefore curing as taught in the prior art is inferior in these examples.

Example 9 also demonstrates the high water resistance provided byorientation of hydrophobic ester functions even though most of thecomponents of the coating are water-soluble. This is achieved equallywell with UV light or electron beam initiation and over plastic, paper,or cardboard. The coatings over paper are generally more water-resistantthan those over plastic as water has permeated the backing. Post-heatingor simply longer storage at ambient conditions further increases thewater-resistance of the coatings on plastic. But it is important to notethat none of the examples in Table 2 block in a high humidity test, andwe have routinely wound up long runs of these coatings on plasticwithout blocking.

EXAMPLE 10

To a pigment (26.0 g, Clariant GDR Pigment Yellow 11-1025, Clariant is atrademark of Clariant Corporation, Coventry, R.I.) was added awater-soluble, ethylenically unsaturated, resin salt prepared asdescribed in U.S Pat. No. 6,559,222 (22.0 g, resin concentratecontaining 41.5 wt. % resin solids in water, amine-neutralized (Sun924-1069, of Sun Chemical Corporation, Fort Lee, N.J.) to pH 6.5), apolymeric hyperdispersant (12.5 g, Solsperse 41090, Solsperse is atrademark and commercially available product of Aecia Corporation,Blackly, Manchester, England), and ammonia (1.0 g, 30% NH.sub.4OH).Next, a silicone defoamer was added (0.5 g, BYK 019, BYK is trademarkand commercially available product of BYK Chemie GmbH, Wesel, Germany)along with partially water soluble, acrylate functional oligomers (18.0gm, Laromer 8765 and 4.0 gm, Sartomer SR 344), and water (16.0 g). Theresulting composition was dispersed for 1 hour with a Cowles blademixer, operating at 2000 rpm, then transferred and dispersed in an Eiger‘Mini’ MK II media mill, operating at 5000 rpm, until full colorstrength was achieved (Eiger is a trademark and commercially availableproduct of Eiger Machinery Corporation, Mundelein, Ill.).

This example illustrates the assembly of a printing ink concentrate(pigment dispersion or base) suitable for letting down or blending into(i.e. manufacturing) a printing ink product comprised of a pigmentdispersed in a ternary, single phase, aqueous, energy curablecomposition containing 12.7 wt. % of a water soluble, ethylenicallyunsaturated resin salt, a partially water soluble oligomer, and 51 wt. %water in the vehicle.

EXAMPLE 11

To the printing ink concentrate prepared in Example 10 (49.0 g) wasadded a partially water soluble, acrylate-functional oligomer (44.0 g,Laromer 8765), a silicone flow additive (1.0 g DC 57), and water (6.0g). The resulting printing ink was stirred to uniformity with a Cowlesblade mixer, operating at 1000 rpm, for 30 minutes.

This example illustrates the assembly of a ternary, single phase,aqueous, printing ink suitable for flexographic printing comprised ofthe ink concentrate prepared in Example 10, a partially water-solubleoligomer, and 28 wt. % water in the vehicle.

EXAMPLE 12

The printing ink prepared in Example 11, having a viscosity of 0.625 Pasat a shear rate of 100 s⁻¹, was printed on a pretreated, low-densitypolyethylene substrate with a Chesnut flexographic/gravure printingpress equipped with a 600 lines/inch anilox and an enclosed,doctor-bladed chamber (Chesnut is a trademark and commercially availableproduct of W.R. Chesnut Engineering Inc., Fairfield, N.J.). The printingplate used was DuPont's Cyrel photopolymer flexographic plate (Cyrel isa trademark and commercially available product of DuPont Company,Wilmington, Del.). A printing press speed of 150 feet per minute (fpm)was used. The printed product was cured with an ESI electron beam cureunit (Reference No. EC30045-1050) operating at a dose rate of 2.5 Mradsand 125 kV and an oxygen level of 200 ppm (ESI is a trademark of EnergySciences, Inc. Wilmington, Mass.). The printed product contained an odorfree, glossy ink film having a print density of 0.97 with an alcohol rubresistance of 24 alcohol rubs. The ink film had 100 percent tapeadhesion with Scotch 600 tape (Scotch 600 is a trademark andcommercially available product of the 3M Company, St. Paul, Minn.).

EXAMPLE 13

To the printing ink prepared in Example 11 was added a photoinitiator(4.0 g, Igracure 500).

This example illustrates the assembly of a ternary, single phase,aqueous, printing ink suitable for flexographic printing comprised ofthe ink concentrate prepared in Example 10, a partially water-solubleoligomer, a photoinitator, and 27 wt. % water in the vehicle.

EXAMPLE 14

The printing ink prepared in Example 13 was printed on a substrate witha flexographic/gravure printing press, as described in Example 12, thencured with a Fusion F600 curing system operating at 300 Watts/inch(Fusion F600 is a trademark and commercially available product of FusionUV Systems, Inc., Gaithersburg, Md.) at 150 fpm. The printed productcontained a glossy ink film having a print density of 0.96 and analcohol solvent (MEK) rub resistance of 20 alcohol rubs. The ink filmhad 100 percent tape adhesion with Scotch 600 tape.

EXAMPLE 15

To the printing ink concentrate prepared in Example 10 (30.0 g) wasadded a water soluble, ethylenically unsaturated, resin salt, preparedas described in U.S. Pat. No. 6,559,222 (10.0 g, resin concentratecontaining 41.5 wt. % resin solids in water, amine-neutralized (Sun924-1069, of Sun Chemical Corporation, Fort Lee, N.J.) to pH 6.5), apartially water soluble, ethylenically unsaturated oligomer (30.0 g,Sartomer SR 344), a silicone wetting agent (1.0 g, DC57), aphotoinitiator (4 g, Igracure 2959) and water (25.0 g). The mixture wasstirred with a Cowles blade mixer, operating at 1000 rpm, for 30minutes, until the photoinitiator dissolved.

This example illustrates the assembly of a ternary, single phase,aqueous, printing ink suitable for gravure printing comprised of the inkconcentrate prepared in Example 10, a water soluble, ethylenicallyunsaturated, resin salt, a partially water-soluble, ethylenicallyunsaturated oligomer, a photoinitiator, and 44 wt. % water in thevehicle.

EXAMPLE 16

The printing ink prepared in Example 15, having a viscosity of 37.1 mPasat a shear rate of 20 s⁻¹ at 25 degrees C., was used to print by directgravure. The printing ink exhibited Newtonian flow behavior over a widerange of shear rates, i.e. 20 s⁻¹ to 2000 s⁻¹ which indicated itssuitability for transfer from the small volume gravure cells of agravure cylinder directly to a substrate. The printing ink was printedon a pre-treated, low-density polyethylene substrate using a handprooferequipped with a 150 lines per inch gravure cylinder. The printed productwas cured with a medium pressure mercury lamp delivering a dose of 180mJ/cm² in the RPC Industries laboratory UV processor. The printedproduct demonstrated a glossy ink film having a print density of 1.38and 100 percent tape adhesion with Scotch 600 tape.

EXAMPLE 17

To the printing ink concentrate prepared in Example 10 (10.0 g) wasadded a water soluble, ethylenically unsaturated, resin salt (10.0 g,resin concentrate containing 39 wt.% resin solids in water andneutralized with ammonia to pH 6.5, as described in PCT InternationalPatent Application WO 99/19369), a partially water-soluble,ethylenically unsaturated oligomer (30.0 g, Sartomer SR 344), a siliconeadditive (0.5 g, DC-57), a photoinitiator (4 g, Igracure 2959), andwater (45.5 g). The mixture was stirred with a Cowles blade mixer,operating at 1000 rpm, for 30 minutes.

This example illustrates the assembly of a ternary, single phase,aqueous, printing ink suitable for ink-jet printing comprised of the inkconcentrate prepared in Example 9, a water soluble, ethylenicallyunsaturated resin salt (neutralized with ammonia), a partially watersoluble, ethylenically unsaturated oligomer, a photoinitiator, and 60wt. % water in the vehicle.

EXAMPLE 18

The printing ink prepared in Example 17, having a viscosity of 17.1 mPasat a shear rate of 100 s⁻¹ at 25 degrees C., was used to print. Theprinting ink exhibited Newtonian flow behavior over a wide range ofshear rates, i.e. 1 s⁻¹ to 1000 s⁻¹ which indicated its suitability forjetting through the small nozzles of an industrial piezo electricink-jet head such as that supplied by Spectra, Inc. of Hanover, N.H. orXaar, plc of Cambridge, UK. The printing ink was applied to apre-treated, low-density polyethylene (LDPE) substrate with a 12 micronsquare bar applicator to simulate a jetted film and cured with an AEBLab 105 electron beam curing unit at a dose of 3.0 mRads and an oxygenlevel of 200 ppm at 100 kV and 75 meters. The printed product containeda glossy ink film having a print density of 1.98 and 100 percent tapeadhesion with Scotch 600 tape.

EXAMPLE 19

To a pigment (5.0 g, Sunfast Blue 15:3 249-1275, Sunfast is a trademarkof Sun Chemical Corporation, Fort Lee, N.J.) was added a water soluble,ethylenically unsaturated, resin salt neutralized with ammonia to pH 6.5(13.5 g, described in PCT International Patent Application WO 99/19369),water (77.5 g) and a photoinitiator (4.0 g, Igracure 2959). Theresulting composition was dispersed for 1 hour with a Cowles blademixer, operating at 2000 rpm, then transferred and dispersed in an Eiger‘Mini’ MK II media mill, operating at 5000 rpm, until full colorstrength was achieved.

This example illustrates the assembly of a binary, single phase,aqueous, energy curable, printing ink suitable for inkjet printingcontaining a colorant, a water soluble, ethylenically unsaturated, resinsalt (neutralized with ammonia), a photoinitiator, and 90 wt. % water inthe vehicle.

EXAMPLE 20

The printing ink prepared in Example 19, having a viscosity of 14.2 mPasat a shear rate of 100 s⁻¹ at 25 degrees C., was used to print. Theprinting ink exhibited Newtonian flow behavior over a wide range ofshear rates, i.e. 1 s⁻¹ to 1000 s⁻¹ which indicated its suitability forjetting through the small nozzles of an industrial piezo electricink-jet head such as that supplied by Spectra, Inc. of Hanover, N.H. orXaar pic of Cambridge, UK. The printing ink was applied to apre-treated, low-density polyethylene (LDPE) substrate with a 12 micronsquare bar applicator to simulate a jetted film and cured with a mediumpressure mercury lamp operating at a dose of 180 mJ/cm² with the RPCIndustries UV processor. The printed product contained an ink filmhaving a print density of 2.26.

EXAMPLE 21

To a pigment (12.5 g, Clariant GDR Pigment Yellow 11-1025) was added awater soluble, ethylenically unsaturated, resin salt prepared asdescribed in U.S. Pat. No. 6,559,222 (38 g) and a pigment dispersant(6.2 g, Solsperse 41090) and talc (2.5 g). Next, a rheology-modifyingsilica (7.5 g, Cabosil M5, Cabosil is a trademark of Cabot Corporation,Billerica Ma.) and partially water soluble, acrylate-functionaloligomers (27.4 g, Laromer 8765 and 6.0 g, Sartomer SR344) were added.The mixture was dispersed for 1 hour with a Cowles blade mixer,operating at 2000 rpm then transferred to and dispersed with awater-cooled, three-roll mill until full color strength was achieved.

This example illustrates the assembly of a ternary, single-phase,aqueous, printing ink suitable for waterless offset printing comprisedof a colorant, a water-soluble, ethylenically-unsaturated, resin salt;partially water-soluble, ethylenically-unsaturated oligomers; and 48 wt.% water in the vehicle.

EXAMPLE 22

The printing ink prepared in Example 21 (0.116 oz.), having a tack of 25at 1200 rpm as measured with a Thwing-Albert Inkometer Model 106(Thwing-Albert is a trademark of Thwing-Albert instrument Company,Philadelphia, Pa.) was applied to a cardboard substrate (Leneta FormN2A, Leneta is a trademark of The Leneta Company, Mahwah, N.J.) andcured with an AEB Lab 105 electron beam curing unit at a dose of 3.0mRads and an oxygen level of 200 ppm at 100 kV and 75 meters per minute.The printed product contained a glossy ink film having a print densityof 1.02.

EXAMPLE 23

To an ethylenically unsaturated, resin salt prepared using anethylenically unsaturated, amine functional oligomer (10 g, Laromer PO94 F) and an ethylenically unsaturated, acid-functional compound (5 g,Itaconic acid, commercially available from Aldrich Chemical, Milwaukee,Wis.) was added a water-soluble, ethylenically unsaturated oligomer (55g, Laromer 8765) and water (30 g).

This example illustrates the assembly of a ternary, single phase,aqueous, coating composition comprised of a 15 wt. % ethylenicallyunsaturated, resin salt (prepared from a basic resin neutralized withacid), a water soluble, ethylenically unsaturated oligomer, and 30 wt. %water.

EXAMPLE 24 (COMPARATIVE)

To a water soluble, ethylenically unsaturated resin (51.3 g, 924-1049resin concentrate containing 39 wt. % resin solids in water andneutralized with ammonia to a pH of 6.5, described in PCT PublishedPatent Application WO 99/19369) was added a partially water soluble,ethylenically unsaturated oligomer (32 g, Laromer 8765) and water (15.5g). The pH of this mixture was adjusted to 4.5 by adding concentratedHCl (1.2 g). To the resulting inhomogeneous mixture was added a wettingagent (0.5 g DC-57). This mixture was blended with a Cowles mixerproducing a poorly emulsified liquid having a viscosity of 100 cP.

This example illustrates the assembly of a ternary, two phase, aqueous,energy curable composition containing a partially water solubleoligomer, a water soluble, ethylenically unsaturated, polymeric,solubilizing resin having only partially neutralized acid groups andacrylate groups, and 48 wt. % water, but at too low a pH to allowincorporation of the resin into a single, aqueous phase.

EXAMPLE 25 (COMPARATIVE)

A portion of the resulting emulsified liquid prepared in Example 24 wascoated (using a #3 wire-wound rod) on saran-coated Mobil ASWpolypropylene and immediately cured by electron beam at a dose of 3.0Mrad and in an atmosphere containing 100 ppm oxygen.

EXAMPLE 26 (COMPARATIVE)

To the remainder of the emulsified liquid prepared in Example 24 wasadded a photoinitiator (3 g, Igracure 2959) and the resulting mixturewas further mixed with a Cowles to form an emulsified liquid. A portionof the emulsified liquid was coated (using a #3 wire-wound rod) on asolvent-inked, saran-coated, Mobil ASW polypropylene and immediatelycured by ultraviolet radiation at a dose of 175 mJ/cm², under an ambientoxygen atmosphere.

EXAMPLE 27 (COMPARATIVE)

To the coating composition prepared in Example 7 (65 g) was added apartially water soluble, ethylenically unsaturated oligomer (35 g,Laromer 8765). The resulting composition was mixed to yield a coatingliquid that slowly phase-separated.

This example illustrates the assembly of a ternary, two phase, aqueous,energy curable composition containing a partially water solubleoligomer, a water soluble, ethylenically unsaturated, polymeric,solubilizing resin having only partially neutralized acid groups andacrylate groups at a pH of 6.5 and water at a ratio where the oligomercould not be incorporated into a single phase composition.

EXAMPLE 28 (COMPARATIVE)

A portion of the blended liquid prepared in Example 27 was coated (using a #3 wire-wound rod) on uncoated card stock (Leneta FormN2A-Opacity, manufactured by Leneta Company, 15 Whitney Rd., Mahwah,N.J.) and immediately cured by electron beam at a dose of 3.0 Mrad underan atmosphere containing 100 ppm oxygen.

EXAMPLE 29 (COMPARATIVE)

To the remaining portion of the liquid prepared in Example 28 was addedphotoinitiator (3.0 g, Igracure 2959). The resulting coating mixture wasmixed to form a uniform dispersion. The liquid was then coated (using a#3 wire-wound rod) on uncoated card stock (Form N2A-Opacity) and curedby ultraviolet radiation at a dose of 175 mJ/cm² under an ambient oxygenatmosphere.

EXAMPLE 30

The results of the performance tests for each comparative coating aredescribed in Table 4 along with the two inventive samples repeated fromearlier Tables to which they most directly compare.

TABLE 4 60 Phase Cure Viscosity Water MEK DEG Adhesion Adhesion ExampleSystem Condition pH Method Substrate (Pa · s.) Rubs Rubs Gloss 610 Tape600 Tape  1c Ternary Single- 6.5 EB Coated PP¹ 0.31 30 19 91 Pass Passphase 24 Ternary Two- 4.5 EB Coated PP¹ 0.11 10 2 80 Fail Fail phase 27Ternary Two- 6.5 EB Cardboard² 0.15 8 7 82 Pass Fail phase  6 TernarySingle- 6.5 UV Coated PP⁵ 0.34 20 21 83 Pass Fail phase 26 Ternary Two-4.5 UV Coated PP⁵ 0.11 12 3 73 Fail Fail phase 29 Ternary Two- 6.5 UVCardboard² 0.15 7 9 71 Pass Fail phase ¹saran coated polypropylene,Mobil ASW, available Exxon-Mobil Corp., Macedon, NY ²uncoated cardboard,Leneta Form N2A-Opacity, available Lenate Co., Mahwah, NJ ³clay coatedpaper, #50 SAPPI, available Sappi Fine Paper N.A., SD Warren Co, Boston,MA ⁴clay coated paper, #23 Strathmore, available Strathmore Papers, EastGranby, CT ⁵saran coated polypropylene, Mobil ASW, printed with Sun OPLam, available Sun Chemical Corporation, Fort Lee, NJThis example illustrates that a single phase composition is superior toa multi-phase composition even when the components and methods of cureare the same. Example 24 differs from Example 1c (and 26 from 6) by 2 pHunits (or 10 exp-4.6 hydrogen ion concentration) which affects the resinsolubility. And Example 27 differs from Example 1c (and 29 from 6) by asmall increase in the proportion of the more reactive (partiallywater-soluble oligomeric) component to a point just to the left of thecloud point curve in a diagram not unlike FIG. 1. The two phase,comparative examples show, both in gloss and mechanical rub resistance,that they are less coherent than their single phase counterparts.

Those skilled in the art having the benefit of the teachings of thepresent invention as hereinabove set forth, can effect numerousmodifications thereto. These modifications are to be construed as beingencompassed within the scope of the present invention as set forth inthe appended claims.

What is claimed is:
 1. An energy curable aqueous composition comprising:(a) water; (b) an ethylenically unsaturated oligomer; (c) a watersoluble ethylenically unsaturated polymeric resin containing neutralizedacidic or basic functional groups which is a surface active materialchemically incorporating hydrophilic and hydrophobic groups; and (d) aphotoinitiator, wherein the composition is a single phase, solution andwherein the photoinitiator consists of a free radical additionpolymerization photoinitiator.
 2. The composition of claim 1 wherein thebasic functional groups of the ethylenically unsaturated resin are aminobasic groups neutralized with an acid.
 3. The composition of claim 1wherein the ethylenically unsaturated resin contains acrylic-functionalgroups, methacrylic-functional groups or a combination thereof.
 4. Thecomposition of claim 1 wherein the ethylenically-unsaturated resincontains carboxylic acid functional groups.
 5. The composition of claim4 wherein the carboxylic acid functional groups are neutralized with amixture of neutralizing agents.
 6. The composition of claim 1 whereinthe ethylenically unsaturated resin is a water soluble styrene/maleicanhydride copolymer, partially esterified with a hydroxy alkyl acrylateor methacrylate functional group.
 7. The composition of claim 6 whereinthe partially esterified styrene/maleic anhydride copolymer is furtheresterified with an alcohol.
 8. The composition of claim 1, wherein theethylenically unsaturated resin has an acid number greater than 80, anda weight average molecular weight between 1,000 and 100,000 daltons. 9.The composition of claim 1, wherein the ethylenically unsaturatedoligomer is at least partially water soluble.
 10. The composition ofclaim 9, wherein the partially water soluble oligomer is selected fromthe group consisting of an acrylate oligomer, a methacrylate oligomer,and combinations thereof.
 11. The composition of claim 10 wherein theacrylate oligomer and methacrylate oligomer respectively contain morethan one acrylate and more than one methacrylate functional groups. 12.The composition of claim 10 wherein the acrylate oligomer is selectedfrom the group consisting of epoxy acrylate, polyether acrylate,polyester acrylate, polyurethane acrylate, polyol acrylates, melamineacrylate, ethoxylatedtrimethanolpropane acrylate, ethoxylateddi(trimethanolpropane) acrylate, ethoxylated pentaerythritol acrylate,ethoxylated dipentaerythritol acrylate, ethoxylated neopentaglycolacrylate, ethoxylated propylene glycol acrylates, and polyethyleneglycol diacrylate; and the methacrylate oligomer is selected from thegroup consisting of: epoxy methacrylate, polyether methacrylate,polyester methacrylate, polyurethane methacrylate, polyol methacrylates,melamine methacrylate, ethoxylated trimethanolpropane methacrylate,ethoxylated di(trimethanolpropane) methacrylate, ethoxylatedpentaerythritol methacrylate, ethoxylated dipentaerythritolmethacrylate, ethoxylated neopentaglycol methacrylate, ethoxylatedpropylene glycol methacrylates, and polyethylene glycol dimethacrylate.13. The composition of claim 9 further comprising a water insolubleoligomer having one or more ethylenically unsaturated groups.
 14. Thecomposition of claim 1 wherein the ethylenically unsaturated resin isselected from the group consisting of polyester, polyurethane,polyacrylic, polyvinyl, polyurea, polyamide, polyol, polycarboxylicacid, polystyrene/maleic anhydride copolymer, and copolymers of themembers of the group.
 15. The composition of claim 1 wherein theethylenically unsaturated resin containing neutralized acidic or basicfunctional groups is less than 60 wt. % based on the total weight of thecomposition.
 16. An energy curable, aqueous, printing ink compositioncomprising: (i) a colorant; and (ii) an energy curable vehicle which isa single phase, aqueous composition of claim 1.